Rear axle not centered, 1/2" more to the passenger side

Discussion in 'Suspension, Steering, Brake & Wheel Topics' started by Azad, Jan 7, 2020.

  1. Azad

    Azad New Member

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    Thanks budro6968,
    but the issue I am writing about is not the drive line ( drive train) offset. I know about that, and it is quite obvious when you check the car from underneath how the whole drive train ( diff yok + drive shaft + transmission) is not centered and shifted to the passneger side, intentionally by GM
    What I am writing about is how much the rear wheels(rims) are sticking out differently in relation to the rear fender. This leads me to one thing, that the attaching points of the rear leaves ( both at the rear shackles and the front pocket)are causing this
     
    budro6968 likes this.
  2. dcozzi

    dcozzi Veteran Member

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    Call me crazy but, I welded the U-bolts to the axle housing on a 9" housing while centered. It did not have Camaro leaf perches, just flat perches and pins for the leaf pack. When I bolted it down centered, the U-bolts slid to the side about 1/4"-1/2" every time.
    I honestly do not know why they were not centered in the first place. Unless the guy who adapted it to a Camaro knew of this harmonics issue and did it intentionally or the perches were already in the correct position for a Camaro. It was a small bearing Ford so it could have came from any car.
     
  3. Fbird

    Fbird Veteran Member Lifetime Gold Member

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    psst if you trim the side of the leaf spring pads.... you will probably need to remove/open up the the locator hole in the bottom pad as the shock mount plate is not going to like you trying to wedge it to 1 side and i doubt there is enough u-bolt clearence to shift it that far .. ;)
     
  4. camaro71/holland

    camaro71/holland Veteran Member

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    From one of my previous posts:

    Shift to the passenger side is normal on our cars and was built in from the factory it seems. Gets noticable when putting large rims on the car and especially with solid bushings. I've measured the difference cut the perches and shifted them 1/2 the measured distance towards the driver side.

    My understanding of why this was done from the factory BTW is to compensate for the weight of the driver and to improve the balance when driving solo.
     
  5. berg2695

    berg2695 Veteran Member

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    I think it is possible that the body symmetry is imperfect, as opposed to the axle mounting. Maybe find a way to measure the distance from the outer edges of the fender openings to the 5/8" gauge holes in the frame rails or some such. I bet that any car that came from the factory perfectly symmetrical had the axle offset in one direction and the rear quarters spot welded off the same amount in the other direction!
     
  6. 79T/Aman

    79T/Aman Veteran Member NastyZ28 Sponsor NastyZ28 Sponsor Lifetime Gold Member

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    As I wrote, "it is offset to dampen harmonics between the front and rear axle" NOT drive line harmonics
    Most are about 3/8" offset but there will be variations in both actual measurements and human error in measuring as well as shift, variations in panels and production tolerances, (1/2" is well within most chassis tolerances for cars of that vintage) I've never seen one perfectly centered and this goes for other platforms as well not just F-bodies, you also can't refer to a 42 year old car and expect it to be perfect regardless of miles especially when the entire rear suspension is rubber mounted.
    What I find puzzling is that you are willing to cut and modify parts therefor making the parts wrong to correct something that does not need correcting ???

    And to expand on why the offset is used is because when the front and rear tires track in a perfect line it creates harmonics as well as slight instability, offsetting the tire paths creates a small amount of resistance/drag canceling out those harmonics.
     
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  7. Azad

    Azad New Member

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    I agree with you Fbird, after reconsideration I decided Not to Do that trimming in the pads. Not many mm's to gain and because of the locator hole as well. Thanks for you input. I also decided not to do anything in this regard, according to my 3rd choice in the main thread
     
  8. biker

    biker Veteran Member

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    If it is purely an aesthetic issue that catches your eye and drives you crazy every time you look at the car, add a spacer behind the one wheel. I know...it sounds kinda bush league to do, but a properly made, purpose-built, safe spacer will accomplish your goal without compromising any aspect of the car. It will be cheap to do and totally eliminates any chance of some sharp eyed jackass ever calling out the issue in front of a bunch of car snobs at a cruise night
     
    budro6968 likes this.
  9. budro6968

    budro6968 Veteran Member

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    Would different backspacing of your Wheels help? IDK. Might just live with it. I get that things like that will bug you. A while back I helped a buddy of mine do some work on a 73 Porsche 914. Major rust. Had to cut half the front end off and section a new part. While taking all the measurements we noticed the Passenger side Front wheel was set back about an inch. I thought it may have taken a hit but no visible damage and all the sheet metal lined up. I don't know if that was built in for Castor? But we changed it to match the wheel base on the other side. Basically squared it up. When it went in for alignment the guy said all he had to do was set the toe. Talk about things that bug you.
     
  10. djorgensen3

    djorgensen3 Veteran Member

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    I know with my car the rearend was offset as well. But when I put composite springs in with new poly bushings(which I know aren't preferred and won't be in there very long) that went in the spring from each side, the rearend became centered perfectly.
     

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